Messages in this thread Patch in this message |  | | From | Cong Wang <> | Date | Mon, 20 Aug 2018 22:29:55 -0700 | Subject | Re: KASAN: use-after-free Read in tipc_group_fill_sock_diag |
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On Sat, Aug 18, 2018 at 5:10 PM syzbot <syzbot+b9c8f3ab2994b7cd1625@syzkaller.appspotmail.com> wrote: > > Hello, > > syzbot found the following crash on: > > HEAD commit: a18d783fedfe Merge tag 'driver-core-4.19-rc1' of git://git.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=14bcc936400000 > kernel config: https://syzkaller.appspot.com/x/.config?x=7eeabb17332898c0 > dashboard link: https://syzkaller.appspot.com/bug?extid=b9c8f3ab2994b7cd1625 > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > syzkaller repro:https://syzkaller.appspot.com/x/repro.syz?x=1374ec4a400000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+b9c8f3ab2994b7cd1625@syzkaller.appspotmail.com > > IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready > IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready > IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready > 8021q: adding VLAN 0 to HW filter on device team0 > ================================================================== > BUG: KASAN: use-after-free in tipc_group_fill_sock_diag+0x7b9/0x84b > net/tipc/group.c:921 > Read of size 4 at addr ffff8801ceb5565c by task syz-executor0/4838 > > CPU: 1 PID: 4838 Comm: syz-executor0 Not tainted 4.18.0+ #196 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:77 [inline] > dump_stack+0x1c9/0x2b4 lib/dump_stack.c:113 > print_address_description+0x6c/0x20b mm/kasan/report.c:256 > kasan_report_error mm/kasan/report.c:354 [inline] > kasan_report.cold.7+0x242/0x30d mm/kasan/report.c:412 > __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432 > tipc_group_fill_sock_diag+0x7b9/0x84b net/tipc/group.c:921 > tipc_sk_fill_sock_diag+0x9f8/0xdb0 net/tipc/socket.c:3322 > __tipc_add_sock_diag+0x22f/0x360 net/tipc/diag.c:62 > tipc_nl_sk_walk+0x68d/0xd30 net/tipc/socket.c:3249 > tipc_diag_dump+0x24/0x30 net/tipc/diag.c:73
Seems we need just unlink the tipc sock before deleting group, otherwise probably have to take a refcnt of group.
For example, moving tipc_sk_leave() down after tipc_sk_remove()?
--- a/net/tipc/socket.c +++ b/net/tipc/socket.c @@ -571,10 +571,10 @@ static int tipc_release(struct socket *sock)
__tipc_shutdown(sock, TIPC_ERR_NO_PORT); sk->sk_shutdown = SHUTDOWN_MASK; - tipc_sk_leave(tsk); tipc_sk_withdraw(tsk, 0, NULL); sk_stop_timer(sk, &sk->sk_timer); tipc_sk_remove(tsk); + tipc_sk_leave(tsk);
/* Reject any messages that accumulated in backlog queue */ release_sock(sk);
> netlink_dump+0x519/0xd50 net/netlink/af_netlink.c:2233 > __netlink_dump_start+0x4f1/0x6f0 net/netlink/af_netlink.c:2329 > netlink_dump_start include/linux/netlink.h:213 [inline] > tipc_sock_diag_handler_dump+0x234/0x340 net/tipc/diag.c:89 > __sock_diag_cmd net/core/sock_diag.c:232 [inline] > sock_diag_rcv_msg+0x31d/0x410 net/core/sock_diag.c:263 > netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2454 > sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:274 > netlink_unicast_kernel net/netlink/af_netlink.c:1317 [inline] > netlink_unicast+0x5a0/0x760 net/netlink/af_netlink.c:1343 > netlink_sendmsg+0xa18/0xfc0 net/netlink/af_netlink.c:1908 > sock_sendmsg_nosec net/socket.c:621 [inline] > sock_sendmsg+0xd5/0x120 net/socket.c:631 > ___sys_sendmsg+0x7fd/0x930 net/socket.c:2114 > __sys_sendmsg+0x11d/0x290 net/socket.c:2152 > __do_sys_sendmsg net/socket.c:2161 [inline] > __se_sys_sendmsg net/socket.c:2159 [inline] > __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2159 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > RIP: 0033:0x457089 > Code: fd b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 > 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff > ff 0f 83 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 > RSP: 002b:00007f3a5d506c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e > RAX: ffffffffffffffda RBX: 00007f3a5d5076d4 RCX: 0000000000457089 > RDX: 0000000000000000 RSI: 0000000020000040 RDI: 0000000000000006 > RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff > R13: 00000000004d4088 R14: 00000000004c8ab0 R15: 0000000000000000 > > Allocated by task 4838: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553 > kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3620 > kmalloc include/linux/slab.h:513 [inline] > kzalloc include/linux/slab.h:707 [inline] > tipc_group_create+0x155/0xa70 net/tipc/group.c:171 > tipc_sk_join net/tipc/socket.c:2766 [inline] > tipc_setsockopt+0x2d1/0xd70 net/tipc/socket.c:2881 > __sys_setsockopt+0x1c5/0x3b0 net/socket.c:1900 > __do_sys_setsockopt net/socket.c:1911 [inline] > __se_sys_setsockopt net/socket.c:1908 [inline] > __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1908 > do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > Freed by task 4837: > save_stack+0x43/0xd0 mm/kasan/kasan.c:448 > set_track mm/kasan/kasan.c:460 [inline] > __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521 > kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528 > __cache_free mm/slab.c:3498 [inline] > kfree+0xd9/0x260 mm/slab.c:3813 > tipc_group_delete+0x2e5/0x3f0 net/tipc/group.c:227 > tipc_sk_leave+0x113/0x220 net/tipc/socket.c:2800 > tipc_release+0x14e/0x12b0 net/tipc/socket.c:574 > __sock_release+0xd7/0x250 net/socket.c:579 > sock_close+0x19/0x20 net/socket.c:1139 > __fput+0x39b/0x860 fs/file_table.c:251 > ____fput+0x15/0x20 fs/file_table.c:282 > task_work_run+0x1e8/0x2a0 kernel/task_work.c:113 > tracehook_notify_resume include/linux/tracehook.h:193 [inline] > exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166 > prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] > syscall_return_slowpath arch/x86/entry/common.c:268 [inline] > do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293 > entry_SYSCALL_64_after_hwframe+0x49/0xbe > > The buggy address belongs to the object at ffff8801ceb55600 > which belongs to the cache kmalloc-192 of size 192 > The buggy address is located 92 bytes inside of > 192-byte region [ffff8801ceb55600, ffff8801ceb556c0) > The buggy address belongs to the page: > page:ffffea00073ad540 count:1 mapcount:0 mapping:ffff8801dac00040 index:0x0 > flags: 0x2fffc0000000100(slab) > raw: 02fffc0000000100 ffffea00073a5088 ffffea00073ae5c8 ffff8801dac00040 > raw: 0000000000000000 ffff8801ceb55000 0000000100000010 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff8801ceb55500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ffff8801ceb55580: 00 fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc > > ffff8801ceb55600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff8801ceb55680: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc > ffff8801ceb55700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with > syzbot. > syzbot can test patches for this bug, for details see: > https://goo.gl/tpsmEJ#testing-patches
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